12 



PRINCIPLES OF ANIMAL BIOLOGY 



prejudice to prevail in some cases, as when he included the whales with 

 the fishes despite his knowledge that they more closely resemble the 

 mammals. 



It was Carolus Linnaeus (1707-1778) (Fig. 8), however, who made the 

 greatest advance in classification. Of a Swedish family and trained to be 

 a physician, he yielded to his interest in natural history and was even- 

 tually named professor of botany in the University of Uppsala. He had a 

 passion for arranging all sorts of natural objects into groups on the basis 

 of like qualities. The choice of qualities to form the basis of this clas- 

 sification was sometimes arbitrary, especially in his earlier years, as 



Fig. 8. — Carolus Linnaeus, 1707-1778, in Lapland dress at the ago of thirty. 



of New York Botanical Garden.) 



{Courtesy 



when he classified plants according to the number of stamens and pistils 

 in their flowers. In later life he recognized that likeness in a single 

 character, in the absence of other similarities, was not a safe ground on 

 which to group organisms. He followed Ray at first in assuming that 

 species have now the characters with which they were created, and in 

 general he held to the "fixity" of species. Yet in his later writings he 

 (juestions whether the several species belonging to one genus ma}^ not 

 have evolved, l^y change, from a single origin in creation. One of 

 Linnaeus's greatest services was the introduction of two terms in the 

 name of a species — the first the name of the genus, the second that of the 

 species — a method which is used at the present time. It was fully 

 developed in his great work, the "Systema Naturae," in which all the 



